Additional file 1 of Sample size and the limits to precision in Pb-isotopic dating by ID-TIMS

Additional file 1. Table S1. Variations of calculated Pb isotopic ratios in the reference material EarlyTime 1x with assumed blank parameters. Table S2. Johnson-Nyquist noise at 24°C as a function of feedback resistance and integration time. Table S3. Comparison of amplifier noise in select mass spectrometers with theoretical (Johnson-Nyquist) noise of 1011 Ohm resistor at 24°C. Table S4. Precision of measurements of the 207Pb/206Pb by TIMS as a function of sample size, ion yield, baseline noise, and measurement conditions (integration times for signal and baseline).